1use std::fmt;23#[cfg(feature = "nightly")]4use rustc_macros::StableHash;56use crate::ExternAbi;78/// Calling convention to determine codegen9///10/// CanonAbi erases certain distinctions ExternAbi preserves, but remains target-dependent.11/// There are still both target-specific variants and aliasing variants, though much fewer.12/// The reason for this step is the frontend may wish to show an ExternAbi but implement that ABI13/// using a different ABI than the string per se, or describe irrelevant differences, e.g.14/// - extern "system"15/// - extern "cdecl"16/// - extern "C-unwind"17/// In that sense, this erases mere syntactic distinctions to create a canonical *directive*,18/// rather than picking the "actual" ABI.19#[derive(Copy, Clone, Debug)]20#[derive(PartialOrd, Ord, PartialEq, Eq, Hash)]21#[cfg_attr(feature = "nightly", derive(StableHash))]22pub enum CanonAbi {23    // NOTE: the use of nested variants for some ABIs is for many targets they don't matter,24    // and this pushes the complexity of their reasoning to target-specific code,25    // allowing a `match` to easily exhaustively ignore these subcategories of variants.26    // Otherwise it is very tempting to avoid matching exhaustively!27    C,28    Rust,29    RustCold,30    RustPreserveNone,3132    /// An ABI that rustc does not know how to call or define.33    Custom,3435    /// ABIs relevant to 32-bit Arm targets36    Arm(ArmCall),37    /// ABI relevant to GPUs: the entry point for a GPU kernel38    GpuKernel,3940    /// ABIs relevant to bare-metal interrupt targets41    // FIXME(workingjubilee): a particular reason for this nesting is we might not need these?42    // interrupt ABIs should have the same properties:43    // - uncallable by Rust calls, as LLVM rejects it in most cases44    // - uses a preserve-all-registers *callee* convention45    // - should always return `-> !` (effectively... it can't use normal `ret`)46    // what differs between targets is47    // - allowed arguments: x86 differs slightly, having 2-3 arguments which are handled magically48    // - may need special prologues/epilogues for some interrupts, without affecting "call ABI"49    Interrupt(InterruptKind),5051    /// ABIs relevant to Windows or x86 targets52    X86(X86Call),53}5455impl CanonAbi {56    pub fn is_rustic_abi(self) -> bool {57        match self {58            CanonAbi::Rust | CanonAbi::RustCold | CanonAbi::RustPreserveNone => true,59            CanonAbi::C60            | CanonAbi::Custom61            | CanonAbi::Arm(_)62            | CanonAbi::GpuKernel63            | CanonAbi::Interrupt(_)64            | CanonAbi::X86(_) => false,65        }66    }67}6869impl fmt::Display for CanonAbi {70    fn fmt(&self, f: &mut fmt::Formatter<'_>) -> fmt::Result {71        // convert to the ExternAbi that *shares a string* with this CanonAbi.72        // FIXME: ideally we'd avoid printing `CanonAbi`, and preserve `ExternAbi` everywhere73        // that we need to generate error messages.74        let erased_abi = match self {75            CanonAbi::C => ExternAbi::C { unwind: false },76            CanonAbi::Rust => ExternAbi::Rust,77            CanonAbi::RustCold => ExternAbi::RustCold,78            CanonAbi::RustPreserveNone => ExternAbi::RustPreserveNone,79            CanonAbi::Custom => ExternAbi::Custom,80            CanonAbi::Arm(arm_call) => match arm_call {81                ArmCall::Aapcs => ExternAbi::Aapcs { unwind: false },82                ArmCall::CCmseNonSecureCall => ExternAbi::CmseNonSecureCall,83                ArmCall::CCmseNonSecureEntry => ExternAbi::CmseNonSecureEntry,84            },85            CanonAbi::GpuKernel => ExternAbi::GpuKernel,86            CanonAbi::Interrupt(interrupt_kind) => match interrupt_kind {87                InterruptKind::Avr => ExternAbi::AvrInterrupt,88                InterruptKind::AvrNonBlocking => ExternAbi::AvrNonBlockingInterrupt,89                InterruptKind::Msp430 => ExternAbi::Msp430Interrupt,90                InterruptKind::RiscvMachine => ExternAbi::RiscvInterruptM,91                InterruptKind::RiscvSupervisor => ExternAbi::RiscvInterruptS,92                InterruptKind::X86 => ExternAbi::X86Interrupt,93            },94            CanonAbi::X86(x86_call) => match x86_call {95                X86Call::Fastcall => ExternAbi::Fastcall { unwind: false },96                X86Call::Stdcall => ExternAbi::Stdcall { unwind: false },97                X86Call::SysV64 => ExternAbi::SysV64 { unwind: false },98                X86Call::Thiscall => ExternAbi::Thiscall { unwind: false },99                X86Call::Vectorcall => ExternAbi::Vectorcall { unwind: false },100                X86Call::Win64 => ExternAbi::Win64 { unwind: false },101            },102        };103        erased_abi.as_str().fmt(f)104    }105}106107/// Callee codegen for interrupts108///109/// This is named differently from the "Call" enums because it is different:110/// these "ABI" differences are not relevant to callers, since there is "no caller".111/// These only affect callee codegen. making their categorization as distinct ABIs a bit peculiar.112#[derive(Copy, Clone, Debug)]113#[derive(PartialOrd, Ord, PartialEq, Eq, Hash)]114#[cfg_attr(feature = "nightly", derive(StableHash))]115pub enum InterruptKind {116    Avr,117    AvrNonBlocking,118    Msp430,119    RiscvMachine,120    RiscvSupervisor,121    X86,122}123124/// ABIs defined for x86-{32,64}125///126/// One of SysV64 or Win64 may alias the C ABI, and arguably Win64 is cross-platform now?127#[derive(Clone, Copy, Debug)]128#[derive(PartialOrd, Ord, PartialEq, Eq, Hash)]129#[cfg_attr(feature = "nightly", derive(StableHash))]130pub enum X86Call {131    /// "fastcall" has both GNU and Windows variants132    Fastcall,133    /// "stdcall" has both GNU and Windows variants134    Stdcall,135    SysV64,136    Thiscall,137    Vectorcall,138    Win64,139}140141/// ABIs defined for 32-bit Arm142#[derive(Copy, Clone, Debug)]143#[derive(PartialOrd, Ord, PartialEq, Eq, Hash)]144#[cfg_attr(feature = "nightly", derive(StableHash))]145pub enum ArmCall {146    Aapcs,147    CCmseNonSecureCall,148    CCmseNonSecureEntry,149}